The microphthalmia transcription factor (Mitf) controls expression of the ocular albinism type 1 gene: link between melanin synthesis and melanosome biogenesis

Mol Cell Biol. 2004 Aug;24(15):6550-9. doi: 10.1128/MCB.24.15.6550-6559.2004.

Abstract

Melanogenesis is the process that regulates skin and eye pigmentation. Albinism, a genetic disease causing pigmentation defects and visual disorders, is caused by mutations in genes controlling either melanin synthesis or melanosome biogenesis. Here we show that a common transcriptional control regulates both of these processes. We performed an analysis of the regulatory region of Oa1, the murine homolog of the gene that is mutated in the X-linked form of ocular albinism, as Oa1's function affects melanosome biogenesis. We demonstrated that Oa1 is a target of Mitf and that this regulatory mechanism is conserved in the human gene. Tissue-specific control of Oa1 transcription lies within a region of 617 bp that contains the E-box bound by Mitf. Finally, we took advantage of a virus-based system to assess tissue specificity in vivo. To this end, a small fragment of the Oa1 promoter was cloned in front of a reporter gene in an adeno-associated virus. After we injected this virus into the subretinal space, we observed reporter gene expression specifically in the retinal pigment epithelium, confirming the cell-specific expression of the Oa1 promoter in the eye. The results obtained with this viral system are a preamble to the development of new gene delivery approaches for the treatment of retinal pigment epithelium defects.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Cell Line, Tumor
  • Cell Nucleus / metabolism
  • Chromatin / metabolism
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology*
  • Dependovirus / genetics
  • Eye Proteins / biosynthesis*
  • Eye Proteins / genetics*
  • Fibroblasts / metabolism
  • Gene Transfer Techniques
  • Genes, Reporter
  • Luciferases / metabolism
  • Melanins / biosynthesis*
  • Melanins / metabolism
  • Melanosomes / metabolism*
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / genetics*
  • Mice
  • Microphthalmia-Associated Transcription Factor
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Mutation
  • NIH 3T3 Cells
  • Pigment Epithelium of Eye / metabolism
  • Plasmids / metabolism
  • Precipitin Tests
  • Promoter Regions, Genetic
  • Protein Binding
  • RNA / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Homology, Nucleic Acid
  • Tissue Distribution
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*
  • Transcription, Genetic
  • Transcriptional Activation
  • Transfection

Substances

  • Chromatin
  • DNA-Binding Proteins
  • Eye Proteins
  • GPR143 protein, human
  • Melanins
  • Membrane Glycoproteins
  • Microphthalmia-Associated Transcription Factor
  • Mitf protein, mouse
  • Transcription Factors
  • RNA
  • Luciferases